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• Building and Repairing Tissues: Proteins are the construction workers of the body.
They build muscles, skin, hair, nails, and even the tiny walls of your cells. When you
get a cut, it is proteins that help repair the wound.
• Enzymes and Hormones: Enzymes are proteins that act like workers in a factory,
speeding up chemical reactions. Without them, digestion, breathing, and even
thinking would be too slow to sustain life. Hormones like insulin are also proteins,
controlling blood sugar and other vital processes.
• Defense System: Antibodies, which fight infections, are proteins. Without them,
even a small cold could become dangerous.
• Transport and Storage: Hemoglobin, the protein in red blood cells, carries oxygen
from the lungs to every cell. Other proteins transport vitamins and minerals where
they are needed.
• Energy Source (in emergencies): Normally, carbohydrates and fats provide energy.
But when these are scarce, proteins can be broken down to supply fuel.
3. Requirements of Proteins
• Daily Needs: On average, an adult requires about 0.8 to 1 gram of protein per
kilogram of body weight per day. For example, a 60-kg person needs about 50–60
grams daily.
• Special Needs:
o Children, pregnant women, and athletes need more protein for growth and
repair.
o Illness or injury also increases protein requirements.
• Sources:
o Animal sources: meat, fish, eggs, milk, cheese.
o Plant sources: pulses, beans, lentils, soy, nuts, whole grains.
Fats: The Energy Bank and Protector
1. What are Fats?
Fats, or lipids, are concentrated sources of energy. They are made up of fatty acids and
glycerol. Unlike proteins, which are builders, fats are like the fuel stations and insulation of
the body.
2. Functions of Fats
• Energy Reserve: Fats provide more than double the energy of carbohydrates or
proteins (9 calories per gram). They are the body’s savings account, storing energy
for times of need.
• Insulation and Protection: Fat under the skin acts like a blanket, keeping the body
warm. Fat around organs like the kidneys and heart acts like a cushion, protecting
them from shocks.
• Absorption of Vitamins: Vitamins A, D, E, and K are fat-soluble. Without fat, these
vitamins cannot be absorbed, leading to deficiencies.